Two sequels to Portable Sound Laboratories' 2006-vintage iMainGo belatedly showed up on our doorstep without much explanation: the 2008-vintage iMainGo 2 ($40) is now a cheaper direct replacement for the original model, still sporting the same look and same zippered neoprene case with rear-firing double 32mm speakers and a soft plastic touch-through window for your iPod or iPhone. Four AAA batteries (included) power iMainGo 2 for up to 30 hours; you're supposed to use thin foam sheets to space thinner (well, virtually every) iPods and iPhones properly so that they can be used through the window. By comparison, the newer iMainGo X ($70) uses an extremely similar body design but packs a 12-hour, 800mAh rechargeable battery for power, and comes with a wall power adapter for refueling. This version has a slicker-looking silver speaker panel with larger 37mm drivers, twin headphone ports and a microphone port in addition to a port for connecting the wall adapter; unlike iMainGo 2, it has a power switch on the outside. Both come with hand straps; X comes with a carrying bag and a second, thick necklace like strap as well. We found the Home Buttons of the iPhone 4 and iPhone 4S somewhat hard to access in both cases when we installed the devices with the included foam spacers -- say nothing of the mismatches between tiny current iPod nanos and shuffles with the big case -- but there are ways to make each device work inside, and the speakers undeniably have more power than anything found inside today's models. It's a shame that these models are so old, but hopefully they'll be retooled with new and more currently iPod/iPhone-appropriate styling.

Editors' Note: iLounge only reviews products in "final" form, but many companies now change their offerings - sometimes several times - after our reviews have been published.
This iLounge article provides more information on this practice, known as revving.